Cook Inlet Wetlands
HEADWATER FEN ECOSYSTEM Wetlands
A stream emerging from under the peat in a Headwater Fen in the Upper Anchor River watershed.
Headwater Fen Ecosystem wetlands are small peatlands occupying the headwaters of first-order streams. They often support diverse plant communities, but a large Headwater Fen on Baldy Ridge had extensive, nearly monospecific areas of Bigelow's sedge (Carex bigelowii). That may be related to the evidence of heavy ATV or snow machine traffic there.
The extensive Carex bigelowii stand in a Headwater Fen on top of Baldy Ridge.
Headwater fens may be particularly important in stream energy cycles. Carbon export from them is important to organisms at the core of the stream's food web. Insects obtain part of their food from carbon processed by micro-organisms. Larger organisms feed on the insects, and the initial carbon source eventually supports larger organisms, such as anadromous fish (Peterson, et.al., 1986).
A Headwater Fen Ecosystem wetland on Baldy Ridge.
All data from wetlands throughout the Cook Inlet Lowlands, not just from the Matanuska-Susitna Valley. Headwater fens are realtively uncommon.
Numbers in paraentheses indicate number of samples.
Peat depth is a minimum, because some sites had thicker peat deposits than the length of the auger used (between 160 - 493 cm).
Water table depth is a one time measurement. At sites with seasonally variable water tables this measurement reflects both the conditions that year, and the time of year.
Redox features with deep depths typically indicate deeper peat deposits, which mask redox indicators so the depth corresponds to the peat thickness.
pH and specific conductance measured in surface water or a shallow pit with a YSI 63 meter calibrated each sample.
Plant Prevalence Index calculated based on Alaska indicator status downloaded from the USDA PLANTS database, which may use different values than the 1988 list.
Headwater Fen Ecosystem Wetland Map Components:
H2: Headwater Fens with water table near the surface most of the growing season. Often dominated by sedges.
H3: Headwater Fens with fluctuating water table, often dominated by shrubs.
H4: Headwater fens with deeper, fluctuating water table, forested.